[CFLAA] Remove tautological comparison

Fixes this (the warning is right, the unsigned value is not negative):
lib/Analysis/StratifiedSets.h:689:53: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
  bool inbounds(StratifiedIndex N) const { return N >= 0 && N < Links.size(); }

llvm-svn: 216987
diff --git a/llvm/lib/Analysis/StratifiedSets.h b/llvm/lib/Analysis/StratifiedSets.h
index 3000d5bc..90e840f 100644
--- a/llvm/lib/Analysis/StratifiedSets.h
+++ b/llvm/lib/Analysis/StratifiedSets.h
@@ -686,7 +686,7 @@
     return Link;
   }
 
-  bool inbounds(StratifiedIndex N) const { return N >= 0 && N < Links.size(); }
+  bool inbounds(StratifiedIndex N) const { return N < Links.size(); }
 };
 }
 #endif // LLVM_ADT_STRATIFIEDSETS_H